Shock mounting



S. MUSIKANT SHOCK MOUNTING Sept. 14, 1954 Filed Feb. 25, 1952 4 g ,MHhVH INVENTOR- S OLOM O N MUSIKANT ATTORNEYS Patented Sept. 14, 1954 SHOCK MOUNTING Solomon Musikant, Los Gatos, Calif., assignor to Vibradamp Corporation,

Santa Clara, Calif., a

corporation of California Application February 23, 1952, Serial No. 272,957

13 Claims. 1

This invention relates to a shock mounting or a spring mounting unit.

It is an object of the invention to provide a shock mounting or a spring mounting unit, utilizing glass fibers as the shock absorption material or spring element.

It is common in the art of shock absorption and resilient mountings to use metal springs, rubber, cork and felt for mountings to resiliently support various elements. However, the art of utilizing glass fibers for resilient mounting of structural members for absorption and dissipation of shock and for spring mountings has heretofore been undeveloped, exceptvas disclosed in the copending application of Joachim Bush, Serial No. 268,049, filed January 24, 1952, now U. S. Patent No. 2,600,843, of common assignee with this application.

It is, therefore, an object of this invention to provide a shock absorption or spring mounting, utilizing glass fibers to absorb shock vibrations and support a structural element in a Amanner that the glass bers will be effective in their resilient support and shock absorption along axes that are angular to one another.

It is another object of the invention to provide a resilient spring or shock absorption mounting, utilizing glass fibers as the supporting structure to resiliently carry the weight of the supported device and, also, for springingly absorbing vibrations of the supported structure angular to the direction of force of the applied load.

It is another object of the invention to provide a shock absorption or spring mounting, wherein the shock absorption or spring material consists of glass bers of staple or continuous length variety bonded together and compressed tocontrolled density to give a specific resilience under the load factor imposed, the glass fibers being disposed in the material generally in a common direction, the shock absorption or spring unit consisting of separate coacting elements constructed of the glass ber material with the glass :fibers of the material in the several elements disposed angular to one another, whereby to absorb shock or secure springing support by the glass :ber material on shock axes that are anguiar and transverse of one another.

Further objects and advantages will become apparent from the drawings and the following description.

In the drawings:

Figure 1 is a horizontal cross-sectional view of a structure incorporating features of this invention.

Figure 2 is a perspective elevational view illustrating a use of a shock absorption or spring unit constructed in accordance with this invention.

Figure 3 is a chart illustrating the stabilization curve of the glass brous material used in the invention.

Figure 4 is a load deflection curve of the stabilized glass brous material.

The glass fiber shock absorbing material of which the spring unit of this invention is constructed is like that material disclosed in the copending application of Joachim Bush, Serial No. 268,049, led Jan. 24, 1952, now Pat. N0. 2,600,843, and produced according to the process disclosed therein. This shock absorbing or spring material constitutes a spring made of glass fibers, wherein the bonded glass fibers act as a multiplicity of cantilever springs for resilient support of a structural member with springing action and with shock absorption and dissipation.

As disclosed in the aforementioned application, the shock absorption or spring material is composed of glass bers that may be produced in any one of several well-known devices by which the glass fibers are collected as a felted assemblage in the form of a mat or a pad. These glass bers may be long continuous length fibers, or they can be short length staple fibers, or a mixture of them. Preferably, the glass fibers used in the shock absorption or spring material are those having a diameter of between 0.00005 and 0.00025 inch, commonly classiedas B fiber in the glass ber industry.

During the course of manufacture of the glass fibers, a binding material is applied to the fibers so that each of the bers is coated with a binding agent when in the assemblage of glass bers composing the glass ber mat or pad. The binding agent is of a type that can be subsequently activated or reactivated to cause a bonding between the fibers at their points of juncture. A common binding agent used for this purpose is a phenol-formaldehyde resin.

However, other binding agents such as the various vinyl resins or styrene or silicon resins, or asphaltic compounds, can be used as the binding agent, depending entirely upon the class of use to which the material is placed. The binding agent can be either a thermosetting or a thermoplastic material, here again depending upon conditions of usage, particularly temperature conditions.

To produce the shock absorption or spring material used in this invention, continuous length or staple length glass fibers of the class heretofore described are brought into an assemblage in the form of a mat or pad. In the normal procedure of producing glass fibers in mat or pad form as collected upon an endless belt moving across the discharge opening of a collecting hood, the glass fibers assume a generally common direction of their disposition relative to one another in that they tend toward parallel arrangement, but due to felting effects of the bers during the course of their laying down on the endless web on which they are collected, the assem bled mat of glass fibers will have fibers disposed angular to one another and angular `to the general direction of lay of the bers, some of the fibers even being normal to the direction of lay.

The mat or assemblage of glass 'fibers collected on the endless Web or belt contains the binder, preferably a phenol-formaldehyde resin in an unpolymerized condition and with the mat being of any desired thickness. It can be generally said that the glass fibers of the mat are positioned horizontally, considering the belt or web being so disposed during collection of vthe bers.

The quantity of glass ber that is brought together in a laminated assemblage is dependent upon the density ofthe glass fibrous material that is to be produced. It has been determined that'by controlling the density of the glass fibrous material it is capable of resiliently supporting pressures of a very broad range, but that each density of -the material will support pressures only `within certain ranges resulting in various degrees of compression ofthe glass fibrous material. For example, a glass brous material having a density of l pound per cubic foot will support pressures of from 0.1 pound per square inch at 15% vdeflection to about 1.5 pounds per square inch at 75% deflection. Glass fibrous material-having-a density of 2O pounds per cubic foot will resiliently support pressures from about 100 pounds per square inch at '15% deflection to about i600 pounds per square inch at 65% deflection.

The assemblage of glass fibrous material is then placed between 'pressure plates to compress the assemblage of glass fibers to the desired density, as for 'example from l pound to 20 pounds persquare foot. Also, thedetermined'density of theglass fibrousmaterial is established when the material fis'at a desired 'thickness or height, dependent upon the dimensions desired in the nished product.

While the glass fibrous material isheld to a desired density at avdesired dimensionbetween the pressure plates, the binding agent on the glass fibers is activated or reactivated to cause a`bond ing between the glass fibers at their various points of contact. Thus, when the pressure is released from the so-treated glass brous material it will retain 'the dimension at which it was compressed.

The so bonded glass lfibrous material is then placed between other pressure plates which stress load the bonded glass -fibrous material to compress it to an extent not less than that at which it will becompressed when supporting the maximum load "to be imposed on the material. A number of such cold working compressions or defiections are given to the material to stabilize the resilience factor of the material. This loading or stressing of the bonded glass fibrous material is occasioned in the same direction as that 4 which will be occasioned upon the material when the supported load is applied.

The effect of the stress loading or cold working of the glass fibrous material is to eliminate the effect of any glass fibers in the material that tend to resist deflection of the material and to fracture those glass bers that are improperly disposed in Ithe material for cooperative resilient support of the load that yis to be imposed on the material.

rlhis stress loading of the glass fibrous material is effective to break or fracture the glass fibers that are improperly disposed in the glass 'brous lmaterial to the extent that they cannot flex to the extent required by the deflection of the material under the load to be applied. Such fibers will fracture or break and leave only the fibers that cooperate to support the load. This action of removing the fibers that tend to resist resilient action of the fibrous material results in stabilizing the resilience factor of the glass fibrous material.

For example, in Figure 3 there is illustrated a chart showing the result of cold working lor compression cycling ofthe boh'ded glass fnbrous material. The material tested consisted of bonded glass fibrous material of ra `density of 6 pounds per cubic foot which was compressed -to 50% of its initial height and yis to Carr-y full load at 40% deflection. Normally cycling or-cold Working is carried 10% beyond themaximum deflection ofthe material under maximum load to stabilize the resilience value of thefmaterialunder full load conditions.

As represented in the chart, it will be seen that the initial 'compression of the material to 50% of its initial height requiredfa load of about 1d pounds per square inch. yAfter the rst two compression cycles the 'load required to compress the material to 50% of its lheight reduced to about 8 pounds per square inch. It will thus Abe seen that the maximum degree of stabilization of 'the resilience factor is obtained in the initial loadings or compression stressings of the material.

Thereafter, up to the first 'ten cycles of stress loadings the pressure required for loading changes only a minor amount, the pressure loading being reduced from about pounds per square inch to slightly over '7 pounds per square inch. At vthis point the glass 'fibrous material is sufficiently stabilized that it Ican Abe 'said -to 'be stabilized for lall practical purposes. However, in the event for the need of extreme accuracy 'for thestabilization'of the resilience factor, the material can befcycled an additional-number of times until atabout fifty 'cycles of stress loadings the product becomes fully stabilized vfor all practical purposes'even of extreme accuracies.

The stabilized product is now capable of producing repeat performance of `springl loading with both a compression and extension of the material 'following substantially the same rate curve as shown by the typical load deflection 'curve'of Figure 4. "The amplitude of vibration absorption is regulated'by thehysteresisloop shown on the load deflection curve. By varying the density of the material for a given load to be supported, and thereby varying the degree of compressionor deflection of the material, Various load deflection curvesmay be obtained with varying curve shapes on the hysteresis loop to secure .the desired control over the amount of energy absorbed by the material in its deflection.

The load deflection curve o'f .Figure 4 .is that of a stabilized material of 6 pounds per-.cubic foot density under a maximum of 45% deiiection stabilized by cold working or stress loading ten times. The original free height of the material being 0.999 inch, with the new free height after stress loading and stabilization being 0.994 inch.

The assemblage of the glass bers coated with phenol-formaldehyde resin is a combination of 5% to 25% phenol-formaldehyde and 95% to 75% glass fibers, with the preferred product containing 15% phenol-formaldehyde and 85% glass bers. The phenol-formaldehyde used as a binder is preferably of from 97% to 40% by weight of phenoLand 3% to 60% by Weight of formaldehyde.

In curing the phenol-formaldehyde resin, for example, the glass fibrous material is heated to a temperature of about 300 F., but which can be varied from about 250 F. to 450 F. There is a loss of about 8% by weight of the phenol product during curing.

In Figures l and 2 there is illustrated a, resilient springing device incorporating the glass fiber material heretofore described, the glass fiber material being so disposed in the springing device or shock absorption device as to absorb movements in different directions, the glass bers of the shock absorbing or springing elements of the device being arranged with their axis of compression angular or normal to the lay of the bers, which lay of the fibers is normal to the axis of compression.

The springing or shock absorption unit I consists of a cylindrical cage II that is composed of two parts IIa and IIb. The cage part IIa is secured to a threaded stud I2 onto which the cage part IIb is threadedly received by the ring I3. The device or apparatus to be supported I4 has a projecting ring I5 which receives the stud I2 so that the cage parts IIa and IIb are on opposite sides of the ring I5. A spindle I6 extends from a stationary support I4 and is positioned Within the cage I0.

A glass fiber shock absorbing element I I is placed between the central portion of the spindle I5 and the stud I2 to support the article I4 in a vertical direction of movement that is transverse of the axis of the spindle. The lay of the glass fibers in the element I'I is generally parallel to the axis of the spindle so that the axis of compression of the element I'I is transverse of the spindle I6. Thus, absorbing relative movement between the spindle and the cage that is transverse of the spindle.

At each end of the spindle I5 there is provided a glass iiber shock absorbing element I8, this element being retained between the washers I8 shouldered on the enlarged central portion 20 of the spindle I5 and the washer 2| that bears against the end of the cage I0.

The glass fiber shock absorbing elements I8 are provided to absorb axial relative movement between the spindle I6 and the cage I0, each of the elements I Il acting as a spring. The elements I8 have the same degree of compression to thus provide a balanced condition upon the spindle I6.

The lay of the glass fibers in the elements I8 is generally transverse of the spindle I6 so that the axis of compression of these elements is axial of the spindle I 6.

The shock absorbing structure II also includes the glass fiber shock absorbing elements 25 that enclose the elements I8. The annular elements 25 have the lay of the glass fibers parallel with the lay of the fibers in the element I'I, and substantially parallel to the axis of the spindle I6'. Thus, the axis of compression of the elements 25 is transverse of the spindle I6.

The elements 25 enclose the elements I8 to support the elements I8 since the transverse shear strength of the glass fiber shock absorbing material is relatively weak, that is, the shear in the plane of the lay of the fibers is not sufficiently great to allow for the reception of large shear stresses on the shock absorbing material. Thus, the glass fiber shock absorbing members 25 support the elements I8 and resist shear action on these elements. Preferably, sleeves 25 separate the elements 25 and I 8 to provide for freedom of action of these elements.

A shock pad 30 of the glass fiber shock absorbing material can be placed in one end of the cage I0 in the event excessive shock is to be accepted in one direction of axial movement of the cage I 0.

While the apparatus disclosed and described illustrates a preferred form of the invention, yet it will be understood that those modifications that fall within the scope of the appended claims are intended to be included herein.

I claim:

1. In a resilient springing shock-absorbing device comprising glass fibers arranged in a plurality of separately acting bodies with each of the bodies comprising glass fibers assembled together in a felted condition, means for retaining said glass fibers in said `condition. and providing a, spring structure with the fibers bonded together at a compressible density, the improvement that consists of having at least one body of glass fibers disposed with the lay of the fibers substantially normal to a rst compression axis and a second body of glass fibers disposed with the lay of the bers substantially normal to 9, second axis of compression, said axes of compression being angular to one another.

2. In a resilient springing shock-absorbing device using glass fibers arranged in a plurality of separately acting bodies with each of the bodies comprising glass bers assembled together in a felted condition, means for retaining said glass fibers in said condition and providing a spring structure with the fibers bonded together at a compressible density, the improvement that consists of having at least one body of glass fibers disposed with the lay of the bers substantially normal to a rst compression axis, and a second body of glass fibers disposed with the lay of the fibers substantially normal to a second axis of compression, said axes of compression being angular to one another, said bodies being so disposed relative to one another that one at least partially encloses the other for support thereof transversely of the axis of compression applied thereon.

3. In a resilient springing shock-absorbing device comprising glass fibers assembled together in a felted condition, means for retaining said glass fibers in said condition and providing a spring structure with the fibers bonded together at a, compressible density with those fibers disposed therein incapable of cooperative resilient support of a load on an established load axis relative to the body of glass fibers being fractured, whereby to eliminate the non-cooperative fibers, the improvement consists of having a rst body of glass fibers disposed with the established load axis thereof parallel with a first load axis of a device to be supported, and a second body of glass fibers disposed with the established load axis thereof parallel to a second load axis of the aeeaaaa device'to be supported, the said load-axesof the said device being angular :to one 1 another.

4. In a resilient springingdevice, a spindle,an assemblage comprising superimposed layers of glass bers assembled together in a felted condition and operatively connected to said spindle, said vbers being bonded togetherat acompressible density with vthose bers disposed therein incapable of cooperative resilient support of `a load on an established load axis relative lto the body of glass bers being fractured, whereby'to eliminate the Ynon-cooperative bers, lsaid glass ber'assemblage comprising, a rst body of glass bers disposed with Vthe established load `axis thereof parallel with a'rst load axis of a device to'be supported, andsaid assemblage'comprising a'second `body'of glass fibers disposed with the established load axis-thereof parallel to a second load axis of thedevice to be supported, the said load axes of the said device being angular to one another, the said bodies of glass bersbeing positioned relative one to the other that-one at least partially encloses the other for support thereof transversely of the established load axis of the body so enclosed.

5. lIn a resilient springing device for supporting apparatus, the combination of, a cage, a spindle in said cage, a rst resilient spring element arranged in said cage and about said spindle, said spring element being composed of an assemblage of glass bers'bonded together as a compressible assemblage with those bers disposed in the assemblage incapable of supporting a load on a given load axis relative to the assemblage fractured, and a second resilient spring structure arranged in said cage and about said spindle, said second spring structure being cornposed of a compressible assemblage with those bers disposed in the assemblage incapable of supporting a load on a given load :axis `relative tothe assemblage fractured, said glass berspring members being spaced longitudinally of said spindle and with their load axes angular to one another.

6. Ina resilient springing device for supporting apparatus, the combination of, a cage, a spindle in said cage, a rst resilient `spring element arranged between saidspindle and said'cage, said spring element being composed of an assemblage of `glass bers bonded together as a compressible assemblage with those bers disposed in the assemblage incapable of supporting a load on va given load axis relative to the assemblage fractured, and a second resilient spring structure arranged between said spindle and said cage, said second spring structure being composed of acompressible assemblage with those bers disposed in theassemblage incapable of supporting a load on a given load axis relative to the assemblage fractured, said members being positioned with their load axes normal to one another.

'7. In a resilient springing device, the combination of. a cage, a spindle within said cage, a rst resilient structure between said spindle and said cage for'absorbing a rstrelative'movenient therebetween, and a second resilient structure between said spindle and said cage for 'absorbing a second relative movement therebetween, said movements being angular to one another, each of said supporting structures being composed of a compressible assemblage or" glass fibers bonded together and compressible on an established axis of compression with those bers incapable of accepting the compression on the given-compression axis fractured, the'compression'axis of each of said supporting structures 'being :parallel with the respective A*direction of movement between said spindle and said .cage supported thereby.

8. In a resilient springing' device, Athe combination of, a cage, a spindle Within said cage,'.a rst glass ber shock absorbing structure .between said spindle and said cage `to absorb relative movement therebetween in a rst direction, and a 'second glass ber shock .absorbing structure between said spindle and said cage for absorbing relativemovement therebetween'in a second'direction,'each of 'saidiglass ber shock absorbing structures being f composed of a compressible assemblage of glass bers bonded together andicompressible on an establishedaxis of compression with those bers incapable of accepting the-compression on the given Vcompression axis-fractured, the compressionaxis of each of said supporting structures beingparallel with the respective direction of movement between saidspindleiand said cage supported thereby.

9. lIn a-resilient springing device. the combinationof, a cage, a spindle withinsaid cage, .a rst glass ber shock absorbing structure between-said spindle :and said cage to absorb `relative movement therebetween transversely'of said spindle, and a, second glass ber shock absorbingstructure between said spindle andsaidcage foriabsorbing relative movement ltherebetween laxial of said spindle, each of said glass ber shock absorbing structures being composed of a'compressible assemblage of 'glass bers bonded together and compressible on anl established axis of compression withthose bers incapable ofiaccepting the compression on the given compression'axis fractured, the compression axis of :each of said supporting structures being parallel `withthe respective direction of movement between said spindle and said cage supportedthereby.

10. In a resilient springing device, the combination of, a cage, a spindle within saidcage, a first glass ber shock absorbing structure between said spindle and said cage to absorb relative movement therebetweentransversely of said spindle, and a second glass ber shock absorbing structure between said spindle and said cage .for absorbing relative movement therebetween axial of said spindle, each of'said glass ber shock absorbing structures being lcomposed of a compressible assemblage of `glass bers bonded ytogether and compressible on an established axis-of lcompression With-those bers incapable of accepting the compression on the given compression axis fractured, the compression axis of each of said supporting-structures being parallel with the respective direction of movement between said spindle and said-cage supported thereby, said rst glass ber shock absorbing structure at yleastpartially enclosing said secondstructure for support thereof transversely of the compression axis yof the said second structure.

11. A resilient springing devicelcomprising yan assemblage of superimposed layers of glass bers assembled together in a felted condition, 'means for retaining said glass bers lin ysaid condition and providing a spring structure with the bers bonded Itogether iat a -compressible 'densityy said glass ber spring structure comprising one body of glass bers'disposed in spaced relationship to a second body of glass bers, said .glass bers being disposed so that the lay'of vthe bers in the rst body is angular to the lay of the bers in the second'body.

12. A resilient springing device comprising a unitary structure composed essentially of glass fibers assembled together in a felted condition, means for retaining said glass fibers in said condition and providing a spring structure with the bers bonded together at a compressible density, said glass ber spring structure comprising one body of glass fibers disposed in spaced relationship relative to a second independently acting body of glass bers, the lay of the fibers in said rst body being angular to the lay of the bers in said second body.

13. In a resilient springing shock-absorbing device comprising glass bers assembled together and retained in a felted condition by means forming a spring structure with the fibers bonded together at a compressible density, the improvement that consists of having one body of glass bers disposed with the lay of the fibers angular 10 to the load axis applied thereon and a second body of glass bers spaced from said rst body of bers and with the lay of the glass bers angular to the lay of the fibers in the first body and angular to a second load axis applied thereon, said load axes being angular to one another.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,184,326 Thomas Dec. 26, 1939 2,331,146 Slayter Oct. 5, 1943 FOREIGN PATENTS Number Country Date 589,383 Great Britain June 19, 1947 

